The Experts below are selected from a list of 1799790 Experts worldwide ranked by ideXlab platform

Jack L. Strominger - One of the best experts on this subject based on the ideXlab platform.

  • Peptide 15-mers of defined sequence that substitute for random amino acid copolymers in amelioration of experimental autoimmune encephalomyelitis
    Proceedings of the National Academy of Sciences of the United States of America, 2005
    Co-Authors: Joel N. H. Stern, Masha Fridkis-hareli, Derin B. Keskin, Zsolt Illes, Jayagopala Reddy, Jack L. Strominger
    Abstract:

    Myelin basic protein (MBP) is a major candidate autoantigen in multiple sclerosis (MS). Its immunodominant epitope, MBP 85-99, forms a complex with human leukocyte antigen (HLA)-DR2 with which multiple sclerosis is genetically associated. Copolymer 1 (Copaxone), a random amino acid copolymer [poly (Y,E,A,K)n] as well as two modified synthetic copolymers [poly (F,Y,A,K)n and poly (V,W,A,K)n] also form complexes with HLA-DR2 (DRA/DRB1*1501) and compete with MBP 85-99 for binding. Moreover, two high-affinity synthetic peptide 15-mers that could inhibit binding even more effectively were previously designed. Here, we show that further-modified peptide 15-mers inhibited even more strongly (in order J5 > J3 > J2) both the binding of MBP 85-99 to HLA-DR2 and IL-2 production by two MBP 85-99-specific HLA-DR2-restricted T cells. J5, J3, and J2 also suppressed both MBP 85-99-induced experimental autoimmune encephalomyelitis (EAE) in humanized mice and proteolipid protein 139-151-induced EAE in SJL/J mice. Moreover, none of these previously uncharacterized peptide inhibitors crossreacted with MBP 85-99- or proteolipid protein 139-151-specific T cells. In both cases, spleen and lymph node cultures stimulated with these peptides produced large amounts of Th2 cytokines (IL-4 and IL-10), and adoptive transfer of established T cell lines suppressed disease induction. These peptide 15-mers provide specific, nonrandom sequences that appear to be at least as effective as random copolymers in suppressing EAE in several models.

  • novel synthetic amino acid copolymers that inhibit autoantigen specific t cell responses and suppress experimental autoimmune encephalomyelitis
    Journal of Clinical Investigation, 2002
    Co-Authors: Masha Fridkishareli, Lars Fugger, Joel N. H. Stern, Laura Santambrogio, Celia F Brosnan, Jack L. Strominger
    Abstract:

    : Copolymer 1 (Cop 1, Copaxone [Teva Marion Partners, Kansas City, Missouri, USA]), a random amino acid copolymer of tyrosine (Y), glutamic acid (E), alanine (A), and lysine (K), reduces the frequency of relapses by 30% in relapsing-remitting multiple sclerosis (MS) patients. In the present study, novel random four-amino acid copolymers, whose design was based on the nature of the anchor residues of the immunodominant epitope of myelin basic protein (MBP) 85-99 and of the binding pockets of MS-associated HLA-DR2 (DRB1*1501), have been synthesized by solid-phase chemistry. Poly (Y, F, A, K) (YFAK) inhibited binding of the biotinylated MBP 86-100 epitope to HLA-DR2 molecules more efficiently than did either unlabeled MBP 85-99 or any other copolymer including Cop 1. Moreover, YFAK and poly (F, A, K) (FAK) were much more effective than Cop 1 in inhibition of MBP 85-99-specific HLA-DR2-restricted T cell clones. Most importantly, these novel copolymers suppressed experimental autoimmune encephalomyelitis, induced in the susceptible SJL/J (H-2(s)) strain of mice with the encephalitogenic epitope PLP 139-151, more efficiently than did Cop 1. Thus, random synthetic copolymers designed according to the binding motif of the human immunodominant epitope MBP 85-99 and the binding pockets of HLA-DR2 might be more beneficial than Cop 1 in treatment of MS.

  • co expression of hla dr3 and dq8 results in the development of spontaneous insulitis and loss of tolerance to gad65 in transgenic mice
    Diabetes, 2000
    Co-Authors: Roshini S Abraham, Jack L. Strominger, Yogish C Kudva, S B Wilson, Chella S David
    Abstract:

    Specific HLA DQ and DR alleles have been associated with susceptibility to type 1 diabetes. HLA DQ8 and DQ2 have been shown to strongly predispose to disease and to be in linkage disequilibrium with at-risk DR4 and DR3 alleles, respectively. Inheritance of a mixed DR3/DR4 haplotype confers the greatest risk. A double transgenic mouse expressing both DR3 and DQ8 was generated to investigate potential major histocompatibility complex class II interactions. The DR3/DQ8 transgenic mice developed a spontaneous loss of tolerance to GAD65, in which the T-cell response to GAD65 was restricted by HLA DR. Although the mice also showed spontaneous insulitis, they did not progress to overt diabetes. Mice expressing either transgene (DQ8 or DR3) alone showed mild infiltration of their islets, which disappeared when DQ8 or DR3 was co-expressed with a resistant DR2 allele or the neutral DQ6 allele. Therefore, in a fashion analogous to human diabetes, the murine model demonstrated a requirement for a combination of at-risk DR and DQ allotypes for the initiation of spontaneous autoimmunity.

  • expression and crystallization of the complex of hla dr2 dra drb1 1501 and an immunodominant peptide of human myelin basic protein
    Proceedings of the National Academy of Sciences of the United States of America, 1998
    Co-Authors: Laurent Gauthier, Jason Pyrdol, Jack L. Strominger, Kathrine J Smith, Don C Wiley, Avtandil Kalandadze, Kai W Wucherpfennig
    Abstract:

    HLA-DR2 is associated with susceptibility to multiple sclerosis (MS). A peptide from human myelin basic protein (MBP, residues 85-99) was previously found to bind to purified HLA-DR2 (DRA, DRB1*1501) and to be recognized by human MBP-specific T cell clones. Soluble HLA-DR2 was expressed in the baculovirus system by replacing the hydrophobic transmembrane regions and cytoplasmic segments of DRalpha and DRbeta with leucine zipper dimerization domains from the transcription factors Fos and Jun. In the expression construct, the MBP(85-99) sequence was covalently linked to the N terminus of the mature DRbeta chain. The recombinant protein was secreted by Sf9 cells infected with the recombinant baculovirus and purified by affinity chromatography. The leucine zipper dimerization domains were then cleaved from the assembled HLA-DR2/MBP peptide complex with V8 protease, and the protein was further purified by anion-exchange HPLC. Analysis by HPLC gel filtration indicated that the HLA-DR2/MBP peptide complex did not have a tendency to aggregate. The purified HLA-DR2/MBP peptide complex readily crystallized by the hanging drop method in 15-18% polyethylene glycol 6000/100 mM glycine, pH 3.5. At a synchrotron radiation source, a crystal with a tetragonal space group diffracted to a resolution of 2.6 A. The expression of such homogenous HLA-DR/peptide complexes may facilitate cocrystallization with T cell receptors as well as other molecules involved in T cell receptor recognition and signaling.

  • specificity and promiscuity among naturally processed peptides bound to hla dr alleles
    Journal of Experimental Medicine, 1993
    Co-Authors: Roman M Chicz, Robert G Urban, Joan C Gorga, Dario A A Vignali, William S Lane, Jack L. Strominger
    Abstract:

    Naturally processed peptides were acid extracted from immunoaffinity-purified HLA-DR2, DR3, DR4, DR7, and DR8. Using the complementary techniques of mass spectrometry and Edman microsequencing, > 200 unique peptide masses were identified from each allele, ranging from 1,200 to 4,000 daltons (10-34 residues in length), and a total of 201 peptide sequences were obtained. These peptides were derived from 66 different source proteins and represented sets nested at both the amino- and carboxy-terminal ends with an average length of 15-18 amino acids. Strikingly, most of the peptides (> 85%) were derived from endogenous proteins that intersect the endocytic/class II pathway, even though class II molecules are thought to function mainly in the presentation of exogenous foreign peptide antigens. The predominant endogenous peptides were derived from major histocompatibility complex-related molecules. A few peptides derived from exogenous bovine serum proteins were also bound to every allele. Four prominent promiscuous self-peptide sets (capable of binding to multiple HLA-DR alleles) as well as 84 allele-specific peptide sets were identified. Binding experiments confirmed that the promiscuous peptides have high affinity for the binding groove of all HLA-DR alleles examined. A potential physiologic role for these endogenous self-peptides as immunomodulators of the cellular immune response is discussed.

Kai W Wucherpfennig - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of t cell receptor binding by bivalent hla dr peptide complexes that activate antigen specific human t cells
    Journal of Biological Chemistry, 2000
    Co-Authors: Heiner Appel, Jason Pyrdol, Laurent Gauthier, Kai W Wucherpfennig
    Abstract:

    Abstract Monovalent major histocompatibility complex-peptide complexes dissociate within seconds from the T-cell receptor (TCR), indicating that dimerization/multimerization may be important during early stages of T-cell activation. Soluble bivalent HLA-DR2·myelin basic protein (MBP) peptide complexes were expressed by replacing the F(ab) arms of an IgG2a antibody with HLA-DR2·MBP peptide complexes. The binding of bivalent HLA-DR2·peptide complexes to recombinant TCR was examined by surface plasmon resonance. The bivalent nature greatly enhanced TCR binding and slowed dissociation from the TCR, with a t of 2.1 to 4.6 min. Soluble bivalent HLA-DR2·MBP peptide complexes activated antigen-specific T-cells in the absence of antigen presenting cells. In contrast, soluble antibodies to the TCR·CD3 complex were ineffective, indicating that they failed to induce an active TCR dimer. TCR/CD3 antibodies induced T-cell proliferation when bound by antigen presenting cells that expressed Fc receptors. In the presence of dendritic cells, bivalent HLA-DR2·MBP peptide complexes induced T-cell activation at >100-fold lower concentrations than TCR/CD3 antibodies and were also superior to peptide or antigen. These results demonstrate that bivalent HLA-DR·peptide complexes represent effective ligands for activation of the TCR. The data support a role for TCR dimerization in early TCR signaling and kinetic proofreading.

  • Visualization of myelin basic protein (MBP) T cell epitopes in multiple sclerosis lesions using a monoclonal antibody specific for the human histocompatibility leukocyte antigen (HLA)-DR2-MBP 85-99 complex.
    The Journal of experimental medicine, 2000
    Co-Authors: Marie Krogsgaard, B E Hansen, Jason Pyrdol, Barbara Cannella, H Ditzel, Jan Engberg, Cameron Raine, Arne Svejgaard, Kai W Wucherpfennig, Lars Fugger
    Abstract:

    Susceptibility to multiple sclerosis (MS) is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 haplotype, suggesting that major histocompatibility complex class II-restricted presentation of central nervous system-derived antigens is important in the disease process. Antibodies specific for defined HLA-DR2-peptide complexes may therefore be valuable tools for studying antigen presentation in MS. We have used phage display technology to select HLA-DR2-peptide-specific antibodies from HLA-DR2-transgenic mice immunized with HLA-DR2 molecules complexed with an immunodominant myelin basic protein (MBP) peptide (residues 85-99). Detailed characterization of one clone (MK16) demonstrated that both DR2 and the MBP peptide were required for recognition. Furthermore, MK16 labeled intra- and extracellular HLA-DR2-MBP peptide complexes when antigen-presenting cells (APCs) were pulsed with recombinant MBP. In addition, MK16 inhibited interleukin 2 secretion by two transfectants that expressed human MBP-specific T cell receptors. Analysis of the structural requirement for MK16 binding demonstrated that the two major HLA-DR2 anchor residues of MBP 85-99 and the COOH-terminal part of the peptide, in particular residues Val-96, Pro-98, and Arg-99, were important for binding. Based on these results, the antibody was used to determine if the HLA-DR2-MBP peptide complex is presented in MS lesions. The antibody stained APCs in MS lesions, in particular microglia/macrophages but also in some cases hypertrophic astrocytes. Staining of APCs was only observed in MS cases with the HLA-DR2 haplotype but not in cases that carried other haplotypes. These results demonstrate that HLA-DR2 molecules in MS lesions present a myelin-derived self-peptide and suggest that microglia/macrophages rather than astrocytes are the predominant APCs in these lesions.

  • crystal structure of hla dr2 dra 0101 drb1 1501 complexed with a peptide from human myelin basic protein
    Journal of Experimental Medicine, 1998
    Co-Authors: Kathrine J Smith, Jason Pyrdol, Laurent Gauthier, Don C Wiley, Kai W Wucherpfennig
    Abstract:

    Susceptibility to multiple sclerosis is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 (DRB1*1501) haplotype. The structure of HLA-DR2 was determined with a bound peptide from human myelin basic protein (MBP) that is immunodominant for human MBP-specific T cells. Residues of MBP peptide that are important for T cell receptor recognition are prominent, solvent exposed residues in the crystal structure. A distinguishing feature of the HLA-DR2 peptide binding site is a large, primarily hydrophobic P4 pocket that accommodates a phenylalanine of the MBP peptide. The necessary space for this aromatic side chain is created by an alanine at the polymorphic DRβ 71 position. These features make the P4 pocket of HLA-DR2 distinct from DR molecules associated with other autoimmune diseases.

  • expression and crystallization of the complex of hla dr2 dra drb1 1501 and an immunodominant peptide of human myelin basic protein
    Proceedings of the National Academy of Sciences of the United States of America, 1998
    Co-Authors: Laurent Gauthier, Jason Pyrdol, Jack L. Strominger, Kathrine J Smith, Don C Wiley, Avtandil Kalandadze, Kai W Wucherpfennig
    Abstract:

    HLA-DR2 is associated with susceptibility to multiple sclerosis (MS). A peptide from human myelin basic protein (MBP, residues 85-99) was previously found to bind to purified HLA-DR2 (DRA, DRB1*1501) and to be recognized by human MBP-specific T cell clones. Soluble HLA-DR2 was expressed in the baculovirus system by replacing the hydrophobic transmembrane regions and cytoplasmic segments of DRalpha and DRbeta with leucine zipper dimerization domains from the transcription factors Fos and Jun. In the expression construct, the MBP(85-99) sequence was covalently linked to the N terminus of the mature DRbeta chain. The recombinant protein was secreted by Sf9 cells infected with the recombinant baculovirus and purified by affinity chromatography. The leucine zipper dimerization domains were then cleaved from the assembled HLA-DR2/MBP peptide complex with V8 protease, and the protein was further purified by anion-exchange HPLC. Analysis by HPLC gel filtration indicated that the HLA-DR2/MBP peptide complex did not have a tendency to aggregate. The purified HLA-DR2/MBP peptide complex readily crystallized by the hanging drop method in 15-18% polyethylene glycol 6000/100 mM glycine, pH 3.5. At a synchrotron radiation source, a crystal with a tetragonal space group diffracted to a resolution of 2.6 A. The expression of such homogenous HLA-DR/peptide complexes may facilitate cocrystallization with T cell receptors as well as other molecules involved in T cell receptor recognition and signaling.

Chella S David - One of the best experts on this subject based on the ideXlab platform.

  • identification of t cell epitopes on human proteolipid protein and induction of experimental autoimmune encephalomyelitis in hla class ii transgenic mice
    European Journal of Immunology, 2004
    Co-Authors: Ashutosh K Mangalam, Meenakshi Khare, Christopher J Krco, Moses Rodriguez, Chella S David
    Abstract:

    Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the CNS that is associated with HLA class II molecules HLA-DR2, -DR3 and -DR4. Previously, it has been difficult to analyze the role of individual HLA molecules in disease pathogenesis due to heterogeneity of MHC genes, linkage disequilibrium, influence of non-MHC genes and contribution of environment. To overcome some of these problems, we have generated HLA-transgenic (tg) mice to investigate function and interaction of these molecules in disease pathogenesis. To investigate the role of individual HLA class II genes in immune responses to human proteolipid protein (PLP), a candidate autoantigen in MS, mice expressing HLA genes DR2, DR3, DR4 (DRB1*0401 and DRB1*0402), DQ6 and DQ8, lacking endogenous class II molecules were immunized with overlapping peptides of PLP. In all tg mice, the majority of the dominant T cell epitopes were clustered mainly to three region; amino acids 31-70, 91-120 and 178-228, of the PLP molecules. We also identified an encephalitogenic epitope PLP(91-110) that induced clinical EAE in HLA-DR3 tg mice. These tg mice had inflammatory infiltrates classically associated with EAE and showed a Th1 cytokine profile. This humanized mouse model of MS will be valuable in deciphering the role of HLA molecules and autoantigens in MS.

  • co expression of hla dr3 and dq8 results in the development of spontaneous insulitis and loss of tolerance to gad65 in transgenic mice
    Diabetes, 2000
    Co-Authors: Roshini S Abraham, Jack L. Strominger, Yogish C Kudva, S B Wilson, Chella S David
    Abstract:

    Specific HLA DQ and DR alleles have been associated with susceptibility to type 1 diabetes. HLA DQ8 and DQ2 have been shown to strongly predispose to disease and to be in linkage disequilibrium with at-risk DR4 and DR3 alleles, respectively. Inheritance of a mixed DR3/DR4 haplotype confers the greatest risk. A double transgenic mouse expressing both DR3 and DQ8 was generated to investigate potential major histocompatibility complex class II interactions. The DR3/DQ8 transgenic mice developed a spontaneous loss of tolerance to GAD65, in which the T-cell response to GAD65 was restricted by HLA DR. Although the mice also showed spontaneous insulitis, they did not progress to overt diabetes. Mice expressing either transgene (DQ8 or DR3) alone showed mild infiltration of their islets, which disappeared when DQ8 or DR3 was co-expressed with a resistant DR2 allele or the neutral DQ6 allele. Therefore, in a fashion analogous to human diabetes, the murine model demonstrated a requirement for a combination of at-risk DR and DQ allotypes for the initiation of spontaneous autoimmunity.

Jason Pyrdol - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of t cell receptor binding by bivalent hla dr peptide complexes that activate antigen specific human t cells
    Journal of Biological Chemistry, 2000
    Co-Authors: Heiner Appel, Jason Pyrdol, Laurent Gauthier, Kai W Wucherpfennig
    Abstract:

    Abstract Monovalent major histocompatibility complex-peptide complexes dissociate within seconds from the T-cell receptor (TCR), indicating that dimerization/multimerization may be important during early stages of T-cell activation. Soluble bivalent HLA-DR2·myelin basic protein (MBP) peptide complexes were expressed by replacing the F(ab) arms of an IgG2a antibody with HLA-DR2·MBP peptide complexes. The binding of bivalent HLA-DR2·peptide complexes to recombinant TCR was examined by surface plasmon resonance. The bivalent nature greatly enhanced TCR binding and slowed dissociation from the TCR, with a t of 2.1 to 4.6 min. Soluble bivalent HLA-DR2·MBP peptide complexes activated antigen-specific T-cells in the absence of antigen presenting cells. In contrast, soluble antibodies to the TCR·CD3 complex were ineffective, indicating that they failed to induce an active TCR dimer. TCR/CD3 antibodies induced T-cell proliferation when bound by antigen presenting cells that expressed Fc receptors. In the presence of dendritic cells, bivalent HLA-DR2·MBP peptide complexes induced T-cell activation at >100-fold lower concentrations than TCR/CD3 antibodies and were also superior to peptide or antigen. These results demonstrate that bivalent HLA-DR·peptide complexes represent effective ligands for activation of the TCR. The data support a role for TCR dimerization in early TCR signaling and kinetic proofreading.

  • Visualization of myelin basic protein (MBP) T cell epitopes in multiple sclerosis lesions using a monoclonal antibody specific for the human histocompatibility leukocyte antigen (HLA)-DR2-MBP 85-99 complex.
    The Journal of experimental medicine, 2000
    Co-Authors: Marie Krogsgaard, B E Hansen, Jason Pyrdol, Barbara Cannella, H Ditzel, Jan Engberg, Cameron Raine, Arne Svejgaard, Kai W Wucherpfennig, Lars Fugger
    Abstract:

    Susceptibility to multiple sclerosis (MS) is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 haplotype, suggesting that major histocompatibility complex class II-restricted presentation of central nervous system-derived antigens is important in the disease process. Antibodies specific for defined HLA-DR2-peptide complexes may therefore be valuable tools for studying antigen presentation in MS. We have used phage display technology to select HLA-DR2-peptide-specific antibodies from HLA-DR2-transgenic mice immunized with HLA-DR2 molecules complexed with an immunodominant myelin basic protein (MBP) peptide (residues 85-99). Detailed characterization of one clone (MK16) demonstrated that both DR2 and the MBP peptide were required for recognition. Furthermore, MK16 labeled intra- and extracellular HLA-DR2-MBP peptide complexes when antigen-presenting cells (APCs) were pulsed with recombinant MBP. In addition, MK16 inhibited interleukin 2 secretion by two transfectants that expressed human MBP-specific T cell receptors. Analysis of the structural requirement for MK16 binding demonstrated that the two major HLA-DR2 anchor residues of MBP 85-99 and the COOH-terminal part of the peptide, in particular residues Val-96, Pro-98, and Arg-99, were important for binding. Based on these results, the antibody was used to determine if the HLA-DR2-MBP peptide complex is presented in MS lesions. The antibody stained APCs in MS lesions, in particular microglia/macrophages but also in some cases hypertrophic astrocytes. Staining of APCs was only observed in MS cases with the HLA-DR2 haplotype but not in cases that carried other haplotypes. These results demonstrate that HLA-DR2 molecules in MS lesions present a myelin-derived self-peptide and suggest that microglia/macrophages rather than astrocytes are the predominant APCs in these lesions.

  • crystal structure of hla dr2 dra 0101 drb1 1501 complexed with a peptide from human myelin basic protein
    Journal of Experimental Medicine, 1998
    Co-Authors: Kathrine J Smith, Jason Pyrdol, Laurent Gauthier, Don C Wiley, Kai W Wucherpfennig
    Abstract:

    Susceptibility to multiple sclerosis is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 (DRB1*1501) haplotype. The structure of HLA-DR2 was determined with a bound peptide from human myelin basic protein (MBP) that is immunodominant for human MBP-specific T cells. Residues of MBP peptide that are important for T cell receptor recognition are prominent, solvent exposed residues in the crystal structure. A distinguishing feature of the HLA-DR2 peptide binding site is a large, primarily hydrophobic P4 pocket that accommodates a phenylalanine of the MBP peptide. The necessary space for this aromatic side chain is created by an alanine at the polymorphic DRβ 71 position. These features make the P4 pocket of HLA-DR2 distinct from DR molecules associated with other autoimmune diseases.

  • expression and crystallization of the complex of hla dr2 dra drb1 1501 and an immunodominant peptide of human myelin basic protein
    Proceedings of the National Academy of Sciences of the United States of America, 1998
    Co-Authors: Laurent Gauthier, Jason Pyrdol, Jack L. Strominger, Kathrine J Smith, Don C Wiley, Avtandil Kalandadze, Kai W Wucherpfennig
    Abstract:

    HLA-DR2 is associated with susceptibility to multiple sclerosis (MS). A peptide from human myelin basic protein (MBP, residues 85-99) was previously found to bind to purified HLA-DR2 (DRA, DRB1*1501) and to be recognized by human MBP-specific T cell clones. Soluble HLA-DR2 was expressed in the baculovirus system by replacing the hydrophobic transmembrane regions and cytoplasmic segments of DRalpha and DRbeta with leucine zipper dimerization domains from the transcription factors Fos and Jun. In the expression construct, the MBP(85-99) sequence was covalently linked to the N terminus of the mature DRbeta chain. The recombinant protein was secreted by Sf9 cells infected with the recombinant baculovirus and purified by affinity chromatography. The leucine zipper dimerization domains were then cleaved from the assembled HLA-DR2/MBP peptide complex with V8 protease, and the protein was further purified by anion-exchange HPLC. Analysis by HPLC gel filtration indicated that the HLA-DR2/MBP peptide complex did not have a tendency to aggregate. The purified HLA-DR2/MBP peptide complex readily crystallized by the hanging drop method in 15-18% polyethylene glycol 6000/100 mM glycine, pH 3.5. At a synchrotron radiation source, a crystal with a tetragonal space group diffracted to a resolution of 2.6 A. The expression of such homogenous HLA-DR/peptide complexes may facilitate cocrystallization with T cell receptors as well as other molecules involved in T cell receptor recognition and signaling.

Lars Fugger - One of the best experts on this subject based on the ideXlab platform.

  • novel synthetic amino acid copolymers that inhibit autoantigen specific t cell responses and suppress experimental autoimmune encephalomyelitis
    Journal of Clinical Investigation, 2002
    Co-Authors: Masha Fridkishareli, Lars Fugger, Joel N. H. Stern, Laura Santambrogio, Celia F Brosnan, Jack L. Strominger
    Abstract:

    : Copolymer 1 (Cop 1, Copaxone [Teva Marion Partners, Kansas City, Missouri, USA]), a random amino acid copolymer of tyrosine (Y), glutamic acid (E), alanine (A), and lysine (K), reduces the frequency of relapses by 30% in relapsing-remitting multiple sclerosis (MS) patients. In the present study, novel random four-amino acid copolymers, whose design was based on the nature of the anchor residues of the immunodominant epitope of myelin basic protein (MBP) 85-99 and of the binding pockets of MS-associated HLA-DR2 (DRB1*1501), have been synthesized by solid-phase chemistry. Poly (Y, F, A, K) (YFAK) inhibited binding of the biotinylated MBP 86-100 epitope to HLA-DR2 molecules more efficiently than did either unlabeled MBP 85-99 or any other copolymer including Cop 1. Moreover, YFAK and poly (F, A, K) (FAK) were much more effective than Cop 1 in inhibition of MBP 85-99-specific HLA-DR2-restricted T cell clones. Most importantly, these novel copolymers suppressed experimental autoimmune encephalomyelitis, induced in the susceptible SJL/J (H-2(s)) strain of mice with the encephalitogenic epitope PLP 139-151, more efficiently than did Cop 1. Thus, random synthetic copolymers designed according to the binding motif of the human immunodominant epitope MBP 85-99 and the binding pockets of HLA-DR2 might be more beneficial than Cop 1 in treatment of MS.

  • Visualization of myelin basic protein (MBP) T cell epitopes in multiple sclerosis lesions using a monoclonal antibody specific for the human histocompatibility leukocyte antigen (HLA)-DR2-MBP 85-99 complex.
    The Journal of experimental medicine, 2000
    Co-Authors: Marie Krogsgaard, B E Hansen, Jason Pyrdol, Barbara Cannella, H Ditzel, Jan Engberg, Cameron Raine, Arne Svejgaard, Kai W Wucherpfennig, Lars Fugger
    Abstract:

    Susceptibility to multiple sclerosis (MS) is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 haplotype, suggesting that major histocompatibility complex class II-restricted presentation of central nervous system-derived antigens is important in the disease process. Antibodies specific for defined HLA-DR2-peptide complexes may therefore be valuable tools for studying antigen presentation in MS. We have used phage display technology to select HLA-DR2-peptide-specific antibodies from HLA-DR2-transgenic mice immunized with HLA-DR2 molecules complexed with an immunodominant myelin basic protein (MBP) peptide (residues 85-99). Detailed characterization of one clone (MK16) demonstrated that both DR2 and the MBP peptide were required for recognition. Furthermore, MK16 labeled intra- and extracellular HLA-DR2-MBP peptide complexes when antigen-presenting cells (APCs) were pulsed with recombinant MBP. In addition, MK16 inhibited interleukin 2 secretion by two transfectants that expressed human MBP-specific T cell receptors. Analysis of the structural requirement for MK16 binding demonstrated that the two major HLA-DR2 anchor residues of MBP 85-99 and the COOH-terminal part of the peptide, in particular residues Val-96, Pro-98, and Arg-99, were important for binding. Based on these results, the antibody was used to determine if the HLA-DR2-MBP peptide complex is presented in MS lesions. The antibody stained APCs in MS lesions, in particular microglia/macrophages but also in some cases hypertrophic astrocytes. Staining of APCs was only observed in MS cases with the HLA-DR2 haplotype but not in cases that carried other haplotypes. These results demonstrate that HLA-DR2 molecules in MS lesions present a myelin-derived self-peptide and suggest that microglia/macrophages rather than astrocytes are the predominant APCs in these lesions.